/**
 * $RCSfile$
 * $Revision$
 * $Date$
 *
 * Copyright 2003-2007 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.smackx;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.Roster;
import org.jivesoftware.smack.RosterEntry;
import org.jivesoftware.smack.RosterGroup;
import org.jivesoftware.smack.Connection;
import org.jivesoftware.smack.filter.PacketExtensionFilter;
import org.jivesoftware.smack.filter.PacketFilter;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smackx.packet.RosterExchange;

/**
 * 
 * Manages Roster exchanges. A RosterExchangeManager provides a high level
 * access to send rosters, roster groups and roster entries to XMPP clients. It
 * also provides an easy way to hook up custom logic when entries are received
 * from another XMPP client through RosterExchangeListeners.
 * 
 * @author Gaston Dombiak
 */
public class RosterExchangeManager {

	private List<RosterExchangeListener> rosterExchangeListeners = new ArrayList<RosterExchangeListener>();

	private Connection con;

	private PacketFilter packetFilter = new PacketExtensionFilter("x",
			"jabber:x:roster");
	private PacketListener packetListener;

	/**
	 * Creates a new roster exchange manager.
	 * 
	 * @param con
	 *            a Connection which is used to send and receive messages.
	 */
	public RosterExchangeManager(Connection con) {
		this.con = con;
		init();
	}

	/**
	 * Adds a listener to roster exchanges. The listener will be fired anytime
	 * roster entries are received from remote XMPP clients.
	 * 
	 * @param rosterExchangeListener
	 *            a roster exchange listener.
	 */
	public void addRosterListener(RosterExchangeListener rosterExchangeListener) {
		synchronized (rosterExchangeListeners) {
			if (!rosterExchangeListeners.contains(rosterExchangeListener)) {
				rosterExchangeListeners.add(rosterExchangeListener);
			}
		}
	}

	/**
	 * Removes a listener from roster exchanges. The listener will be fired
	 * anytime roster entries are received from remote XMPP clients.
	 * 
	 * @param rosterExchangeListener
	 *            a roster exchange listener..
	 */
	public void removeRosterListener(
			RosterExchangeListener rosterExchangeListener) {
		synchronized (rosterExchangeListeners) {
			rosterExchangeListeners.remove(rosterExchangeListener);
		}
	}

	/**
	 * Sends a roster to userID. All the entries of the roster will be sent to
	 * the target user.
	 * 
	 * @param roster
	 *            the roster to send
	 * @param targetUserID
	 *            the user that will receive the roster entries
	 */
	public void send(Roster roster, String targetUserID) {
		// Create a new message to send the roster
		Message msg = new Message(targetUserID);
		// Create a RosterExchange Package and add it to the message
		RosterExchange rosterExchange = new RosterExchange(roster);
		msg.addExtension(rosterExchange);

		// Send the message that contains the roster
		con.sendPacket(msg);
	}

	/**
	 * Sends a roster entry to userID.
	 * 
	 * @param rosterEntry
	 *            the roster entry to send
	 * @param targetUserID
	 *            the user that will receive the roster entries
	 */
	public void send(RosterEntry rosterEntry, String targetUserID) {
		// Create a new message to send the roster
		Message msg = new Message(targetUserID);
		// Create a RosterExchange Package and add it to the message
		RosterExchange rosterExchange = new RosterExchange();
		rosterExchange.addRosterEntry(rosterEntry);
		msg.addExtension(rosterExchange);

		// Send the message that contains the roster
		con.sendPacket(msg);
	}

	/**
	 * Sends a roster group to userID. All the entries of the group will be sent
	 * to the target user.
	 * 
	 * @param rosterGroup
	 *            the roster group to send
	 * @param targetUserID
	 *            the user that will receive the roster entries
	 */
	public void send(RosterGroup rosterGroup, String targetUserID) {
		// Create a new message to send the roster
		Message msg = new Message(targetUserID);
		// Create a RosterExchange Package and add it to the message
		RosterExchange rosterExchange = new RosterExchange();
		for (RosterEntry entry : rosterGroup.getEntries()) {
			rosterExchange.addRosterEntry(entry);
		}
		msg.addExtension(rosterExchange);

		// Send the message that contains the roster
		con.sendPacket(msg);
	}

	/**
	 * Fires roster exchange listeners.
	 */
	private void fireRosterExchangeListeners(String from,
			Iterator remoteRosterEntries) {
		RosterExchangeListener[] listeners = null;
		synchronized (rosterExchangeListeners) {
			listeners = new RosterExchangeListener[rosterExchangeListeners
					.size()];
			rosterExchangeListeners.toArray(listeners);
		}
		for (int i = 0; i < listeners.length; i++) {
			listeners[i].entriesReceived(from, remoteRosterEntries);
		}
	}

	private void init() {
		// Listens for all roster exchange packets and fire the roster exchange
		// listeners.
		packetListener = new PacketListener() {
			public void processPacket(Packet packet) {
				Message message = (Message) packet;
				RosterExchange rosterExchange = (RosterExchange) message
						.getExtension("x", "jabber:x:roster");
				// Fire event for roster exchange listeners
				fireRosterExchangeListeners(message.getFrom(),
						rosterExchange.getRosterEntries());
			};

		};
		con.addPacketListener(packetListener, packetFilter);
	}

	public void destroy() {
		if (con != null)
			con.removePacketListener(packetListener);

	}

	protected void finalize() throws Throwable {
		destroy();
		super.finalize();
	}
}
